<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="app">
        <h1>
            当前计数：{{counter}}
        </h1>
        <button v-on:click="add">+</button>
        <button v-on:click="sub">-</button>
    </div>
    <div>

    </div>
    <script>
        const app = new Vue({
            el: "app",
            data: {counter : 0},
            methods:{
                add: function () {
                    this.counter++;
                    console.log('add被执行');
                },
                sub: function () {
                    this.counter--;
                    console.log('sub被执行');
                }
            }
        })
    </script>
</body>
</html>